After years of mine approvals and expansions, we finally have a picture of what will be left after mining.
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My report The Hole Truth: the mess coal companies plan to leave in NSW found state government approved plans to leave behind at least 45 large and potentially toxic mining pits across the Hunter Valley.
Together, these mining voids cover an area greater than the size of Sydney Harbour.
The Minerals Council came to the industry’s defence, pointing to the potential for coal mine voids to become a series of lakes to attract tourists.
If that is the plan, it wasn’t in the planning documents, the environmental impact assessments or government approvals.
It is true many coal mine voids are designed to partially fill with water, but very slowly, typically taking around 350 years – not quite the tourist playground the Minerals Council would have us imagine.
Government-approved mine planning documents describe post-mining landscapes designed to divert water away from the mine void, not into it.
So is the Minerals Council’s idea to turn mines into recreational lakes feasible?
Coal mine voids have been filled and used as lakes in other countries, notably Germany. But there, water is far more plentiful.
It would certainly be possible to somewhat speed up the filling of the voids with water, and possibly, some lakes could be made. There are, after all, lakes in the Upper Hunter Valley.
But creating lakes that can be used for recreation or aquaculture requires high water quality.
Over time, most of the lakes will become more and more saline and loaded with heavy metals. Preventing this would require significant inputs of fresh water.
In NSW, unlike Germany, it is doubtful there will be enough water for many of the pits that remain when the mines close.
So backfilling mining voids is the best option to ensure a positive environmental outcome.
If we don’t plan for this, it can be a massively expensive undertaking. And in NSW, no company has been required to plan to fill the hole left by mining.
The studies and planning required to ensure mine voids can become positive environmental features have simply not been done.
With the price of coal low and demand waning, big mining companies that should properly clean up after themselves are rapidly exiting the NSW coal business.
Once these companies leave the Hunter Valley, the kind of major earthworks required to minimise the impact of final voids - or fill them back in - will be impossible.
It’s a different story in the United States. Forty years ago, they introduced legislation requiring coal mines to be properly cleaned up when they close. All pits must be filled, returning the landscape to its original contour.
And in the world-class mining state of NSW? Coal mining companies have proposed the cheapest option – and the worst possible outcome for the community who remain when the mines close. This has been fully supported by the government.
If the coal industry’s long-term legacy in NSW is to be positive, government needs to act rapidly and decisively. Without better rules, bigger funds and strong oversight, industry will leave NSW with a series of saline craters it cannot afford to rehabilitate.
